Telphone system with automatic ringing disconnect.



F. SCHOENWOLFi TELEPHONE SYSTEM WITH AUTOMATIC RINGING DISCONNECT.

APPLICATION FILED NOV. 21. I914.

ll WW 1 Wm Patented July 23, 1918.

fiZUEHZER FZ ELThUEHZ/Z/UZZ ing and called substations A and spectivelyeach terminating in line circuits rupts the link or cord talkingconductors and rnwrrnn "STATES rarnnr or rrpn.

' FRED SCJEECENWOLF, 0E CHICAGO, ILLINOIS, ASSIGNCR TO KJELIOGGSWITCIIBOARD AJSIII SUPPLY COMPANY, 0T CHICAGO, ILLINCIS, A CCRJPORATICN0R IIIIJJEN 01$.

I TELEPHONE SYSTEM WITH AUTOMATIC RING-INC DISCONNECT.

IRIRJLSR.

Application filed November a7, 1914:. Serial No. Warsaw To all whom itmay concern Be it known that I, FIRED SononNwoLr, a citizen of theUnited States of America, resident of Chicago, county of Cook, and Stateof Illinois, have invented certain new and useful Improvementsinj'Iel'ephone Systems with Automatic Ringing Disconnect, of which thefollowing is a specification.

My invention-relates to telephone systems and has to do moreparticularly with auto matic ringing systems such as are provided foroperators cord circuits, one of the principal objects of my inventionbeing to provide an improved circuit arrangement whereby the applicationof ringing current to the called line is interrupted and a disconnectsignal given should the calling sub scriber replacehis receiver prior toreceivin a response from the called substation.

n the accompanying drawing I have illustrated the preferred embodimentofmy invention, the system shown includin callrehaving theusual line relayLR, cut-ofi' relay CO and line jacks. The line circuits shownare Whatare known as multiple lamp circuits in which a line lamp is provided foreach jack so that when a call is initiated a. line signal appearsbefore'each of the calling line jacks and any one .of a pluralityof'operators may seize this call preferably to the exclusion of others.

The preferred form of cord circuit C is'arranged for interconnecting thetelephone lines and includes an answering plug AP and calling plug ClPconnected by talkin conductors indicated by heavily marke lines. Inanswering a call an. operator inserts an answeringplug AP into a linejack whereby the high resistance test relay 'I is energized to connectthe answering supervisory relay AS in circuit with the cut-olf relay COso that relay AS is energized and connects the operators telephone 0 incircuit with the cord and thus with calling line. The answeringvtiprela'y'A'll also energizes to prevent the premature lighting of theanswering supervisory lamp AL. In extending the call to the wanted linethe operator inserts the calling plug CI whereby the calling sleeverelay CS energizes to again disconnect the operators telephoneSpecification of Letters Patent.

Patented July as, rare;

from the cord circuit. depresses the proper plunger of the ringing keyRK'which connects the proper ringing generator by the common contacts ofthe key, causes an energization of a ringing con- Theoperator then,

trol relay RC followed by the periodlc en- A ergizations of aninterrupter relay IR by a circuit through the interrupter I. "When thesubscriber responds to the call a calling tip relay C'I energizesinterrupting the locking circuit for the ringing control relay RC tostop further application of ringingcurrent and efface the callingsupervisory lamp CL.

Should the calling subscriber replace his receiver prior to the responseof the called subscriber link disconnect relay IJD energizes and in viewof the fact that the lock mg circuit for the ringing control relay RC iscontrolled through contacts of relay LD, the ringing control relaydee'nergizes and prevents further application of ringing current to thecalled line.

'Ihe energization of relay Ll) also interdevices employed in thepreferred embodiment of my invention and their functions, Iv

will now describe more in detail the operation of the system shown.

A subscriber at substation A desiring to call, removes his receiver toestablish a cir-' cuit for the corresponding line relay LR whereby theline signals before the different associated jacks are lighted. 'Ihefirst oper ator to seize the call by the insertion of an answering plugAP in one of the calling line jacks, connects high resistance test relaI and cut-ofl' relay COin series effectmg the energization of T. Theclosing of alternate contact I of relay 'I connects the comparativelylow resistance answering sleeve relay AS in series with cut-0d relay"the shunting of its winding b control relay RC traced from through thewinding thereof, alternate con- CO whereby relay AS energizes closinits,

alternate contact 2 to connect its win ing directl to the sleeve strandof the cord indepen ent of the contact of the test relay, Thereforeshould relay T restore due to paratively low resistance of A relay ASstill remains energized through ts locking contact 2. Due to the flow ofcurrent throu h the windings of AS and T over the ca ling line andthrough theanswerlng tip relayAT, said relay AT energizes to interruptits normal contact 3 and prevent a premature lighting of the answeringsupervisory lamp L and premature energlzation of the link disconnectrelay-LD. Also responsive to energization of AS its alternate contacts4, 5 are closed to connect the .operators telephone 0 in bridge of thetalkin conductors of the. cord and thus to the ca ling telephone line.

Should a second operator lnsert a plug APinto another jack of the callinline subsequent to the insertion ofthe rst plug, the test relay T ofthis second cord does not energize due to the shunting of lts winding bythe relay AS of the first cord so that the second operator is unable tocommunicate with the calling subscriber because .her telephone set isnot: connected. Therefore this second operator again withdraws heranswering plug AP The first operator having ascertained that connectionis desired with. substation B tests a jack thereof in the usualmannerand finding the line idle inserts the calling plug -CP in a jackthereof. This act connects calling sleeve relay CS and cut-off relay COin series causing their energization, the energization of CO removingthe substation control of its line signals and extend ing the connectedjack and cord to the called line. The energization of CS by interruptingits normal contacts 9, 10, again disconnects the operators telephonefrom the cord. The operator now depresses the proper plunger by ringingkey RK whereby the associated generator is connected to the ringingconductor 6. The actuation of the ringing plunger to its fully depressedposi- 8 which are closed while the plunger is 7 fully depressed but notwhen in its intermediate position. The closing of alternate contact 8establishes a circuit for ringing battery tact 8, normal contacts 11,12, and alternate contact 13, to ground. Relay RC therefore energizesclosin its alternate contact 14 to establish a direct locking circuitfor its winding through normal contact 11, and 12 and alternate contact13 to ground.

It will be noted that the locking circuit for ringing control relay RCis traced will be described; the com-' tip relay C through. normallyclosed contacts of relays LD and CT thereby placing the disconnection ofringing current under control of both the calling and called substationsas Relay RC having energized, interrupts its normal contacts 17, 18 tointerrupt the talking strand and closes its alternate contact 19 toestablish an operating circuit for interrupter relay IR throughinterrupter I. Relay IR is therefore periodically energized toalternatel connect ringing current and in circuit with the called lineby action of its contacts 20, 21.

Upon response of the called subscriber and the first followindeenergization of IR acircuit for tip re ay CT- is established tracedfrom ground through the winding thereof, normal contact 20, alternatecontact 22, over the line and returning through the winding of CS tobattery. The resulting energization of CT efi'ects an int'errix tion ofits normal contact 12 which it wil {be remembered is included in thelocking circuit of RC. Therefore relay RC deenergizes opening itsalternate contact 19 and maintaining the interrupter relay IR inert. Theclosing of the normal contacts 17, 18 establishes the continuity of thetalking circuit between the two substations.

Assuming now that the connection has been extended to the called lineand that its substation was being rung, as before described, but thatthe calling subscriber replaces his receiver prior to receiving a re- Isponse from the called substation. In such case the circuit foranswering tip relay AT is interrupted causing its restoration whereby acircuit for link disconnect relay LD and supervisory lamps AL, CL isestablished. 1015 The circuit for relay LD is established from batterythrough winding thereof, normal contact 3 and' alternate contacts 26,13-to ground. Relay LD therefore energizes to interrupt the talkingconductors of the link and thereby operatively disconnect the link fromthe calling line. Although this energization of LD interrupts theinitial energizing circuit for AS and T by the opening of normalcontacts 27, said relays AS and T are maintained energized throughalternate contact 27 to ground over contacts 26, 13. The groundconnection from alternate contact 13 to normal contact 3, previouslytraced, is also effective to li ht supervisory lamp AL and the closing 0alternate contact 11 of relayLD lights calling supervisory lamp CL overa circuit traced from battery through CL, alternate contact 11, normalcontact 12 to ground at alternate contact 13. The operator havingobserved the two signals AL .and CL lighted, withdraws plugs AP and CPfrom their respective jacks, the withdrawal of plug CP causing therestoration of relay CS whereby its 415 lighting of lamps AL and CL andthe ener- Lat/area alternate contact 13 is interrupted. As reas alreadydescribed. The operator will now lays LD, T and AS are held up over acircuit through this alternate contact 13, it will be seen that they arerestored when said contact is interrupted.

ltwill be observed that when the subscriber A replaces his receiverprior to receiving a response from the called substation and relay LDenergized to operatively disconnect the cord from the calling line,cutofi' relay CO thereof restored so that the line of substation Awasavailable for immediate recall. Therefore if the subscriberat substationA desires to initiate a recall without awaiting the removal of plug All?from its jack, by again removing the receiver, line relay LR isenergized to light the associated line signals so that the same oranother operator may take the call. 4

When a connection has been efiected between substations A and B in amanner as above described and both receivers are ofl their switch-hooks,establishing a conversational circuit, the replacing of these receiverswill light supervisory lamps AL and CL. Assuming the subscriber at B isthe first to replace his receiver the circuit for relay CT isinterrupted causing the closure of its normal contact 12 andestablishing a circuit for lamp CL from ground at alternate contact 13of CS, normal contacts 12, 11, 14:, 7 and lamp CL to battery. Thereplacing of thereceiver at substation A causes the deenergization of ATfollowed by the energization of Ll) and the lighting of lamp AL withdrawthe two plugs restoring the apparatus to normal.

' It will be noted that relay Ll) is a slow restoring type, this beingto prevent the seizing of a recall by more than one link circuit. Thatis,- assuming a connection is es tablished between substations A and Band that after conversation the subscribers have replaced theirreceivers to bring about the gization of LD. Should the callingsubscriber at A initiate a recall prior to the removal of plug AP, theassociated line signals will of course be lighted and should anotheroperator than the one which controls cord C seize this call, upon thewithdrawal of plug CP of C the locking circuit for relays LD, T and ASis interrupted at alternate contact 13 of CS. Now if relays LD, T andASwere fast relays, and relay Ll) should restore prior to T and AS itwill be seen that due to the closing of normal con tact 27 of LD, relayAS would remain locked up over the sleeve strand and therefore theoperator of cord C would have her telephone connected to the callingline in multiple with the telephone of the other op erator who hasseized the recall. But due to the slowness of relay Ll), relays AS andservice and instantaneous disconnect and recall are provlded, togetherwith automatic ringing which when applied to a called line may beinterrupted by a control exercised from either connected substationtogether with means for establishing the usual disconnect signal of twosupervisory lamps.

lln Working out-my invention l have applied it to a preferred form ofcord or link circuit but I contemplate using it in con nection withother circuits than that shown. lt will also be apparent .that changesand modifications will readily occur to those skilled in the art afterbecoming familar with my invention and therefore it do not de sire to belimited to the exact structure as shown and described but aim'to coverall that which comes within the spirit and scope of the appended claims.

Having described my invention, what ll claim as new and desire to secureby United States Letters Patent, is:

1. A telephone system comprising telephone lines, an operators linkcircuit for interconnecting said lines, operator controlled means forapplying ringing current and continuing such application to the calledline, and means for interrupting such application of ringing current bya control ex- -ercised at both the calling and called subcontrolledmeans for initiating the operation of said means, and means controlledby both supervisory relays for interrupting said application of ringingcurrent.

v 3. A telephone system comprising telephone lines, an operators linkcircuit for interconnecting said lines, a relay at each end of the linkcircuit operable over the telephone line connected at that end, meansfor applying ringing current and continuing such application to thecalled line, operator controlled means for initiating the opera tion ofsaid means, and circuit connections including contacts of both of saidrelays whereby said application of ringing current may be interrupted bya control exercised at both the calling .and called substations.

4:. .A telephone system comprising telephone lines, an operators linkcircuit for interconnecting said lines, means for applying ringingcurrent and continuing such application to the called line, a pair ofsupervisory signals for the link circuit and means controlled over thecalling line for mterrupting such application of ringing current to-thecalled-line and lighting sald supervisory signals for disconnection.

5. A telephone system comprising telephone lines, an operators linkcircuit-for 1nterconnecting said lines, means for intermittentlyapplying ringing current to the" called line, operator controlled meansfor initiating the operation of said ringing means, and means controlledby either the calling or the called subscriber for disconnecting theringing current from the called subscribers line.

6. A telephone system comprising a call-' sociating his line from thesaid link circuit,

and means responsive to such disassociation for interrupting theapplication of ringing current to the line of sa1d called subscriber;

8. A telephone system comprising a'calling and a called subscribersline, a link circuit for connecting said lines, means included in saidlink circuit for automaticallg applying ringing current to the saidcalle subscribers line, electromagnetic means responsive to a controlexercised at the substation of the calling line for disassociating saidcalling line and said link circuit, and means controlled by saidelectromagnetic means for interrupting the application of ringingcurrent to the called subscribers line.

9. A telephone system comprising telephone lines, an operators linkcircuit for connecting said lines, means included in said link circuitfor intermittently applying ringin current to the called line, adisconnect re ay for disconnecting the calling subscribers line from thelink circuit, and means controlled by said disconnect relay forinterrupting the application of ringing current to said calledsubscribers line.

10. A telephone system comprising telephone lines, a link circuit forinterconnecting said lines, means for intermittently applying ringingcurrent to a called one of said lines, and means controlled at thesubstation of a calling one ofsaid lines for disassociating his linefrom said link circuit and for mterrupting such application of ringingcurrent.

11. A telephone system comprising a pair of connected telephone lines,means for applying ringing current to one of said lines, meanscontrolled at the substation of the other of said lines fordisassociating said lines and for interrupting the application ofringing current to the first one of said lines.

12. A telephone system comprising a pair of connected telephone lines,means for applying ringing current to one of said lines means controlledat the substation of one 0t said lines for disassociating said lines,and means controlled at the substation of either of said lines forinterrupting such application of ringing current.

13. A telephone system comprising a pair of telephone lines, anoperators link circuit for connecting said lines, means included in saidlink circuit for applying ringing current to one of said connectedlines, a disconnect relay controlled at the substation of the other ofsaid lines for disassociatin said last line and said link circuit, andmeans controlled by said disconnect relay for disconnecting the ringingcurrent from the first one of said lines.

14. A telephone s stem including a calling and a called telepll linkcircuit for connecting said lines in conversational circuit, means forapplying ringing current and continuing such application of the same tosaid called line, a pair of supervisory signals for said link circuit,and means controlled by the calling subscriber for interrupting suchapplication of ringing current to the called line and for operating bothof said supervisory signals.

' 15. A telephone system including a calling subscribers line and acalled subscribers line, an o erators link circuit for connecting saidines in conversational circuit, a source of ringing current, means forintermittently applying said ringing current to the said called line, anoperator s switch for initiating the operation of said intermittentmeans, and means controlled by the callin subscriber for causing thecessation of sai intermlttent means.

16. A. telephone system including a calling subscribers telephone lineand a called subone line, an opcrators All that/add link circuitconnecting said lines in conversational circuit, a source of ringingcurrent, means for intermittentl appl ing said ringing current to thecal ed su scri'bers line, operator controlled means for initiating theoperation of said ringing means, and electromagnetic means controlled bythe calling subscriber for preventing the intermittent application ofringing current'to the called subscribers line,

18. 'A telephone system including a calling subscribers line and acalled subscribers line, an operators link circuit provided With a pairof terminals for connectmg said lines, a source of ringing current,operator controlled means tor connecting said ringing current to thesaid called subscribers line, a relay controlled over the callingsubscribers line, and means controlled by said relay for preventing afurther application of ringing current to the said called subscribersline.

19. A telephone system including a calling subscribers line and a calledsubscriber s line, an operators cord circuit for connecting said lines,a source of ringing current, means for intermittently applying saidringing current to the called subscribers line, operator controlled.means for initiating the operation of said applying means, and meanscontrolled by the replacement of the receiver at the calling substationfor preventing said applying means from further connecting ringingcurrent to the called subscribers line.

20. A telephone system including a calling connection for operating saidsupervisor signal and for preventing the further application of saidringing current to said called subscribers line.

21. A telephone system including a calling subscribers telephone lineand a called subscribers telephone line, means provided with manualterminals for connecting said lines, ringin mechanism including a relayadapted to be energized intermittently to apply ringing current to thecalled subscribers line,

means controlled by a central ofiice operator for associatin saidmechanism With the said called subscri ers line, and automatic meanscontrolled by the calling subscriber for disassociating said ringingmechanism from the said called subscribers line thereby preventingfurther intermittent applications of ringing current to the calledsubscribers line.

22. A telephone system including a calling subscribers telephone lineand a called subscribers telephone line, an operator's link circuit foruse in connecting said lines, a source of ringing current, a relayadapted to be operated intermittently to connect said ringing current tosaid called subscribers line, a ringing control relay controlling theoperation of said first relay, means for operating said ringing controlrelay to initiate the operation of said first relay, and electroma neticmeans controlled by the calling su scriber for deenergizing said ringingcontrol relay to prevent further operation of said first relay, therebypreventing further intermittent applications of ringing current to thesaid called subscribers line.

Si ed by me at Chicago, county of Cook, and tate of llllinois, in thepresence 0t two witnesses.

FRED SGHOJENWOLF. Witnesses:

Gunner: 1E. MR, M. R. Roonronn.

Alli

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